Needles and catheters are routinely inserted or injected into a patient's body for various purposes or indications. One type of indication that involves such insertion is the placement of vascular lines or catheters, for instance, the placement of a central venous catheter (CVC). A CVC is typically used to administer fluids (e.g., intravenous (IV) drugs, chemotherapeutic agents, blood, or saline) into the body in medical situations in which large fluid transfer volume and/or high fluid transfer rate is desired. Common CVC insertion targets include an internal jugular vein, located in the neck; a subclavian vein, located in the chest; or a femoral vein, located in the groin. A medical procedure known as the Seldinger technique is typically employed for placing CVCs within the body.
The Seldinger technique involves several steps. To establish venous access and CVC insertion via the Seldinger technique, a needle is first placed or inserted into the patient's body at a location expected to correspond to a target vein. A guidewire is then advanced or extended through the needle into the vasculature or vessel in which the needle resides. The needle is subsequently removed while a portion of the guidewire remains retained within the vessel, and a portion of the guidewire remains outside the patient's body. Next, a CVC is advanced over the guidewire into the vessel. Finally, the guidewire is removed, leaving a portion of the CVC within the vessel.
One problem that can arise during CVC placement via the Seldinger technique is a misplacement of either or both of the needle and the CVC. For example, an unintended puncture or tear of a venous wall and/or the placement of one or both of the needle and the CVC into an artery (i.e., an unintended arterial cannulation) can occur, which may result in serious and expensive complications including severe bleeding, emergency vascular surgery, stroke, and possibly death.
Manometry is a technique that has been used for verifying that an appropriate type of blood vessel has been targeted during catheterization (e.g., in association with the Seldinger technique). Conventionally, during manometry directed toward vascular target verification, an extension set (e.g., a 50 centimeter extension tube set) is attached to a needle or a catheter (e.g., an 18-gauge needle or catheter) that has been inserted into a vessel. Blood flows from the patient's body into the needle or catheter, and further flows into an elevated section of tube along the extension set, thereby forming a blood column.
Visible properties of the blood column within the elevated section of tube are assessed by a surgeon or other medical personnel. The assessment of the blood column, for example, a height attained by the blood column, gives an indication as to the pressure of the blood within the vessel under consideration. Such an assessment can enable the surgeon to verify a venous or an arterial placement of the needle or the catheter. However, needle or catheter occlusion or patient state or condition can impact the visible properties of the blood column, and hence the surgeon's assessment, which can lead to a false conclusion about needle or catheter placement. For instance, in a hypotensive patient, an inadvertent arterial needle insertion may not be readily apparent from a naked-eye assessment of blood column height within the elevated section of tube.
Additionally, it has been found that many physicians do not routinely utilize manometry for verifying needle or catheter placement. Furthermore, a needle or a catheter may become dislodged or displaced after performing manometry, which may render its vascular location uncertain. Accordingly, the risk of accidental arterial cannulation during CVC insertion procedures has not been eliminated by the use of manometry. It has also been suggested that the use of manometry may increase the risk of infection or air embolism within the patient.
Ultrasound has been conventionally utilized for determining the position of objects within the body, including needles, guidewires, and catheters. However, images captured with ultrasound may not be adequately informative or clear. For example, ultrasound may be unable to accurately or consistently differentiate between certain tissue types (e.g. between venous tissue and arterial tissue). There have been reported instances of accidental arterial cannulation during CVC placement despite the use of ultrasound. In addition, ultrasound systems or apparatuses belonging to a medical facility are typically shared among multiple groups or departments of that medical facility, and hence may not always be readily available. Additionally, the use of ultrasound for verifying vascular targeting can be time consuming, and thus may be undesirable in critical or emergency situations. Furthermore, the use of ultrasound systems can be comparatively costly and labor intensive.